\section{Special Numeric Values} \label{Special Numeric Values} TECO maintains several internal variables which record conditions within TECO. The variable name is equivalent to the current contents of the variable and may be entered as a numeric argument to TECO commands. When the command is executed, the current value of the designated variable becomes the numeric argument of the command. Some of the characters which stand for specific values associated with the text buffer have been introduced earlier in this manual. For example, the dot character {\tt .}, which represents the current pointer position, may be used in the argument of a T command. The command {\tt .,.+5T} causes the 5 characters following the buffer pointer to be typed out. When this command is executed, the number of characters preceding the buffer pointer is substituted in each case for the ``dot''. The addition is then carried out, and the command is executed as though it were of the form {\tt m,nT}. Table~\ref{Characters Associated With Numeric Quantities} lists all of the characters which have special numeric values. Any of these characters may be used as numeric argument in place of the value it represents. \begin{table}[h] \caption{\bf{Characters Associated With Numeric Quantities}} \label{Characters Associated With Numeric Quantities} \end{table} \nopagebreak \begin{list}{}{\labelsep 20pt} \item [CHARACTER] FUNCTION \item [{\tt B}] Always equivalent to zero. Thus, {\tt B} represents the position preceding the first character in the buffer. \item [{\tt Z}] Equivalent to the number of characters currently contained in the buffer. Thus, {\tt Z} represents the position following the last character in the buffer. \item [{\tt .}] Equivalent to the number of characters between the beginning of the buffer and the current position of the pointer. Thus {\tt .} represents the current position of the pointer. \item [{\tt H}] Equivalent to the numeric pair {\tt B,Z}, or {\em from the beginning of the buffer up to the end of the buffer}. Thus, {\tt H} represents the whole buffer. \item [{\tt nA}] Equivalent to the ASCII code for the {\em .+n+1}th character in the buffer (that is, the character to the right of buffer pointer position {\em .+n}). The expression {\tt -1A} is equivalent to the ASCII code of the character immediately preceding the pointer and {\tt 0A} is equivalent to the ASCII code of the character immediately following the pointer (the current character). If the character position referenced lies outside the bounds of the text buffer, this command returns a -1. \item [{\tt Mq}] The {\tt Mq} command (execute the contents of the text storage area of Q-register q as a command string) may return a numeric value if the last command in the string returns a numeric value and is not followed by a {\tt }. \item [{\tt Qq}] Equivalent to the value stored in the number storage area of Q-register q. \ifnotintecoeight \item [{\tt :Qq}] Equivalent to the number of characters in the text storage area of Q-register q. {\em [Not in TECO-8]} \fi \item [{\tt \bs}] Backslash is equivalent to the numeric value of the digit string in the text buffer at the current pointer position, interpreted in the current radix. The pointer is moved to the end of the digit string. \item [\caret {\tt B}] {\tt } (\caret {\tt B}) is equivalent to the current date via the following equations: \begin{list}{}{\labelsep 10pt} \item[OS/8:] \caret {\tt B} = (((month*32)+day)*8)+((year-1970)\&7)+k where k = 4096 if year$>$1977 and k=0 otherwise \item[RT-11:] \caret {\tt B} = (((month*32)+day)*32)+year-1972 \item[RSTS/E:] \caret {\tt B} = ((year-1970)*1000)+day within year \item[RSX-11:] \caret {\tt B} = ((year-1900)*16+month)*32+day \item[VAX/VMS:] \caret {\tt B} = ((year-1900)*16+month)*32+day \item[TOPS-10:] \caret {\tt B} = (((year-1964)*12+month-1)*31+day-1) \end{list} \item [\caret {\tt E}] {\tt } (caret/E) determines whether or not the {\tt P} command (and related operations) append a form feed to the contents of the buffer on output. If \caret{\tt E} is -1, a form feed is appended; if \caret{\tt E} is 0, no form feed is appended. Each time text is read into the text buffer TECO sets the \caret{\tt E} flag. If the text read terminated due to a form feed (i.e., if the text buffer was loaded with a {\em complete page}), \caret{\tt E} is set to -1. If the text read terminated because the buffer was filled to capacity before a form feed was encountered or because there was no form feed (i.e., the text buffer was not loaded with a {\em complete page}), \caret{\tt E} is set to 0. In TECO-11, you can set the \caret{\tt E} flag's value directly, overriding the value set by the most recent buffer read. Be sure to use only values of 0 or -1; other values may cause unpredictable results. \item [\caret {\tt F}] {\tt } (caret/F) is equivalent to the current value of the console switch register. \iftecotenonly \item [{\tt n} \caret {\tt F}] {\tt n} is the terminal number plus 200000 (octal) for job {\tt n}'s terminal. -1\caret{\tt F} is the terminal number plus 200000 (octal) for your job's terminal. The result is 0 if the specified job is detached or if there is no such job. {\em [TECO-10 only]} \fi \item [\caret {\tt H}] {\tt } (caret/H) is equivalent to the current time of day via the following equations: \begin{list}{}{\labelsep 10pt} \item[OS/8:] \caret{\tt H} = 0 \item[RT-11:] \caret{\tt H} = (seconds since midnight)/2 \item[RSTS/E:] \caret{\tt H} = minutes until midnight \item[RSX-11:] \caret{\tt H} = (seconds since midnight)/2 \item[VAX/VMS:] \caret{\tt H} = (seconds since midnight)/2 \item[TOPS-10:] \caret{\tt H} = 60ths of a second since midnight (or 50ths of a second where 50 Hz power is used) \end{list} \item [\caret {\tt N}] {\tt } (caret/N) is the end of file flag. It is equivalent to -1 if the file open on the currently selected input stream is at end of file, and zero otherwise. \ifnotintecoeight \item[\caret {\tt S}] {\tt } (caret/S) is equivalent to the negative of the length of the last insert, string found, or string inserted with a {\tt G} command, whichever occurred last. To back up the pointer to the start of the last insert, string found, etc., type \caret{\tt SC}. {\em [Not in TECO-8]} \fi \item[\caret {\tt T}] {\tt } (caret/T) is equivalent to the ASCII code for the next character typed at the terminal. Every \caret{\tt T} command executed causes TECO to pause and accept one character typed at the terminal. See the {\tt ET} flag description (section~\ref{Mode Control Flags}) for variations. \item[{\tt :}\caret {\tt T}] Reads and decodes the next keystroke typed at the terminal. The decoded keystroke is returned in a manner similar to that used for immediate ESCape sequence commands (see section \ref{Immediate ESCAPE-Sequence Commands}), i.e., via {\tt } and {\tt } codes, as follows: \begin{list}{}{\labelsep 10pt} \item[{\tt } 0] Normal character, {\tt } is ASCII value. \item[{\tt } 1] Control character (except ESCape or CSI); {\tt } is ASCII value of control char. A typed {\tt } yields {\tt } 1 {\tt } 13, and subsequent \caret {\tt T} or : \caret {\tt T} does not return a {\tt } . \item [{\tt } 2] Same as immed ESC seq {\tt } 0 \item [{\tt } 3] Same as immed ESC seq {\tt } 1 \item [{\tt } 4] Same as immed ESC seq {\tt } 2 \iftecoelevenonly \item [{\tt } 5] Same as immed ESC seq {\tt } 3 \end{list} {\em [TECO-11 only]} \item[\caret {\tt Y}] {\tt } (caret/{\tt Y}) is equivalent to {\tt .+\caret S,.}, the {\tt n,m} numeric argument spanning the text just searched for or inserted. This value may be used to recover from inserting a string in the wrong place. Type \caret{\tt YXSFR}\escape to store the string in Q-register S and remove it from the buffer. You can then position the pointer to the right place and type {\tt GS} to insert the string. {\em [TECO-11 only]} \item[\caret {\tt Z}] {\tt } (caret/Z) is equivalent to the total space occupied by text in the Q-registers (including the command line currently being executed). {\em [TECO-11 only]} \fi \item[\caret \caret {\tt x}] The combination of the Control-caret (double caret or double up-arrow) followed by any character is equivalent to the value of the ASCII code for that character. The {\tt x} in this example may be any character that can be typed in to TECO. \end{list} \subsection*{Mode Control Flags} The following mode control flags return numeric values. The use of these flags is described below in section~\ref{Mode Control Flags}. \begin{list}{}{\labelsep 20pt} \item [{\tt ED}] Equivalent to the current value of the edit level flag. \item [{\tt EH}] Equivalent to the current value of the help level flag. \item [{\tt EO}] Equivalent to the version number of the version of TECO which is currently being run. This manual describes TECO-11 Version 40, TECO-8 Version 7, and TECO-10 Version 3. \ifnotintecoeight \item [{\tt ES}] Equivalent to the current value of the search verification flag. {\em [Not in TECO-8]} \fi \item [{\tt ET}] Equivalent to the current value of the type out control flag. \item [{\tt EU}] Equivalent to the current value of the upper/lower case flag. \iftecoelevenonly \item [{\tt EV}] Equivalent to the current value of the edit verify flag. {\em [TECO-11 only]} \fi \ifnotintecoeight \item [\caret {\tt X}] {\tt } (caret/{\tt X}) is equivalent to the current value of the search mode flag. {\em [Not in TECO-8]} \fi \end{list}